Structural unit

ABSTRACT

A structural unit, in particular a grinding wheel has a hole pattern for sucking away swarf from a machining surface. The hole pattern has at least three recesses which are arranged essentially along a first spiral line. The hole pattern also has at least three further recesses which are arranged essentially along a second spiral line which intersects the first spiral line in a region of at least one recess.

This application claims priority under 35 U.S.C. §119 to patent application no. DE 10 2012 201 329.6, filed on Jan. 31, 2012 in Germany, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

A structural unit, in particular a grinding wheel, having a hole pattern has already been proposed. There is already a multiplicity of grinding wheels with hole patterns, what are known as multihole grinding wheels, such as are known, for example, from patent specification EP 0 781 629 B1.

SUMMARY

A structural unit, in particular a grinding wheel, is proposed, having a hole pattern, in particular for sucking away swarf from a machining surface, with at least three recesses which are arranged at least essentially along a first spiral line, and with at least three further recesses which are arranged at least essentially along a second spiral line which intersects the first spiral line in the region of at least one recess. In this context, various structural units which seem expedient to a person skilled in the art may be envisaged such as, for example, brake disks or shower heads, but, in particular, a grinding wheel or a grinding plate are to be understood. In this case, a “grinding wheel” is to be understood, in particular, to mean a unit which forms the tool of a grinding machine, in particular of an eccentric grinding machine, and, during operation, is directly in contact with a workpiece for the removal of material. The unit preferably has at least one carrier layer and at least abrasive layer. The carrier layer is preferably composed of a paper, a foil, a fabric, a fiber or a combination. However, other materials which seem expedient to a person skilled in the art may also be envisaged. The abrasive layer preferably has granulation. Especially preferably, the unit is intended to be connected to a grinding plate via the carrier layer. In this context, a “grinding plate” is to be understood, in particular, to mean a unit of a grinding machine, in particular of an eccentric grinder, which is intended to receive a tool, in particular a grinding wheel. The grinding plate preferably has at least one main surface of extent which serves as a reception surface for the tool. Especially preferably, the grinding plate is driven by the grinding machine. Furthermore, in this context, a “hole pattern” is to be understood, in particular, to mean an arrangement of recesses. In this context, a “recess” is to be understood, in particular, to mean a through hole. It is preferably a round hole, but other hole shapes which seem expedient to a person skilled in the art may also be envisaged. Moreover, a “spiral line” is to be understood in this context to mean, in particular, a curve which runs around a spiral axis. Preferably, a spacing of points of the mapping with respect to the spiral axis changes strictly monotonically in relation to the angle. Especially preferably, mapping of the spiral line in a polar coordinate system can be differentiated at least simply continuously. Furthermore, “at least essentially” is to be understood in this context to mean, in particular, that a distance from a stipulated value, in particular a stipulated position, amounts, in particular, to less than 50%, preferably to less than 25% and especially preferably to less than 10% of a diameter of the recess.

An advantageous distribution of recesses can be achieved as a result of the configuration according to the disclosure of the structural unit having the hole pattern.

It is proposed, furthermore, that at least a large part of the recesses is arranged along spiral lines having in each case at least three recesses. In this context, “large part of the recesses” is to be understood, in particular, to mean at least more than 50%, preferably at least more than 70% and especially preferably at least more than 90% of the recesses. Advantageous surface utilization can be achieved by virtue of the configuration. Furthermore, uniform distribution can be achieved.

Moreover, it is proposed that at least a large part of the recesses is arranged at intersection points of the spiral lines. Uniform surface utilization can thereby advantageously be achieved.

Furthermore, it is proposed that the at least two spiral lines be contradirectional to one another with respect to a spiral axis of the spiral lines. Furthermore, in this context, “contradirectional” is to be understood, in particular, to mean that the spiral lines run around their spiral axes in opposite directions away from the respective starting points or toward the respective starting points. Especially advantageous distribution of the recesses can thereby be achieved.

Furthermore, it would be conceivable that the distances in each case from two recesses which succeed one another directly along a spiral line, in the case of at least a large part of the recesses, vary by less than 60%, especially preferably by less than 50%, from the maximum distance between two successive recesses. Especially uniform distribution of the recesses can thereby be achieved.

Moreover, it would be conceivable that the recesses which are arranged along the same spiral line are arranged in each case in an angular range of less than 360° along the respective spiral line.

It is proposed, further, that the contradirectional spiral lines differ from one another in their number. This is to be understood, in particular, to mean that a number of spirals which run in one direction is different from the number of spirals which are contradirectional with respect to these spirals.

What can advantageously be achieved thereby is that an asymmetric hole pattern with advantageous surface utilization and with advantageous surface distribution is achieved.

Moreover, it is proposed that the number of codirectional spiral lines and/or the number of contradirectional spiral lines correspond/corresponds to a number of the Fibonacci sequence. In this context, a “number of the Fibonacci sequence” is to be understood, in particular, to mean any positive number which is part of the general Fibonacci sequence (0, 1, 1, 2, 3, 5, 8, 13, 21, . . . ). The sequence commences with the numbers 0 and 1, all further numbers being obtained by the addition of the two preceding numbers. Preferably, this is to be understood, in particular, to mean a number of the Fibonacci sequence which is greater than or equal to 3. Especially preferably, this is to be understood, in particular, to mean a number of the Fibonacci sequence which is greater than or equal to 8.

In particular, it is proposed that the number of codirectional spiral lines and the number of contradirectional spiral lines correspond to two successive numbers of the Fibonacci sequence. Especially preferably, the ratio of the two numbers to one another corresponds at least approximately to the golden section. In this context, “at least approximately” is to be understood to mean, in particular, that a deviation from a stipulated value amounts, in particular, to less than 10%, preferably to less than 5% and especially preferably to less than 2%. Furthermore, in this context, the “golden section” is to be understood, in particular, to mean a ratio Φ. The ratio Φ is given by

$\mspace{20mu} {\varphi = {\frac{2 + \sqrt{\text{?}}}{\text{?}} \approx {{1.618\;.\text{?}}\text{indicates text missing or illegible when filed}}}}$

What can advantageously be achieved thereby is that the recesses are distributed uniformly on the surface and recesses can be prevented from lying directly one behind the other in the radial direction.

It is proposed, furthermore, that the at least one spiral line corresponds at least approximately to a Fibonacci spiral. In this context, a “Fibonacci spiral” is to be understood, in particular, to mean a spiral which is composed of quarter circles. Preferably, the sequence of the radii of the quarter circles corresponds to the Fibonacci sequence, and in this case the numbers of the Fibonacci sequence are to be understood to be unitless. Especially preferably, the quarter circles are placed one against the other so as always to be rotated through 90° with respect to one another. An especially uniform spiral line can thereby advantageously be achieved, as a result of which, in turn, advantageous surface distribution can be achieved.

Moreover, it is proposed that at least 50% of the recesses which are arranged along a spiral line have in each case a minimum spacing with respect to a center point which differs from all the minimum spacings with respect to the center point of recesses which are arranged along the two adjacent codirectional spiral lines, so that at least 50% of the recesses of one spiral line lie on radii which are related to the center point and which differ from radii on which the recesses of the adjacent spiral lines lie. Preferably, at least 70% of the recesses which are arranged along a spiral line have in each case a minimum spacing with respect to a center point which differs from all the minimum spacings with respect to the center point of recesses which are arranged along the two adjacent codirectional spiral lines. Especially preferably, at least 90% of the recesses which are arranged along a spiral line have in each case a minimum spacing with respect to a center point which differs from all the minimum spacings with respect to the center point of recesses which are arranged along the two adjacent codirectional spiral lines. In this case, a “center point” is to be understood in this context to mean, in particular, a center point of a main plane of extent of the structural unit. It would be conceivable, furthermore, that at least 50% of the recesses which are arranged along a spiral line have in each case a minimum spacing with respect to a center point which differs from all the minimum spacings with respect to the center point of recesses which are arranged along the two adjacent codirectional spiral lines and the spiral lines adjacent to the adjacent spiral lines.

The situation can thereby advantageously be prevented where at least a large number of recesses lies in the circumferential direction directly in the shadow, that is to say on the same radius with respect to the center point, of another recess, as a result of which, with a small fraction of holes, maximum coverage in the circumferential direction can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages appear from the following drawing description. The drawings illustrate two exemplary embodiments of the disclosure. The drawings and disclosure contain numerous features in combination. A person skilled in the art will expediently also consider the features individually and combine them into appropriate further combinations.

FIG. 1 shows a structural unit according to the disclosure with a hole pattern and with spiral lines in a diagrammatic illustration, and

FIG. 2 shows a system with the structural unit according to the disclosure and with an alternative structural unit according to the disclosure and a machining surface in a diagrammatic illustration.

DETAILED DESCRIPTION

FIG. 1 shows a structural unit 10 according to the disclosure with a hole pattern 16 for sucking away swarf from a machining surface 18. The structural unit 10 is formed by a grinding wheel 12. Furthermore, the structural unit 10 has recesses 20 which are arranged essentially along a first spiral line 22, and further recesses 24 which are arranged essentially along a second spiral line 26 which intersects the first spiral line 22 in the region of a recess 20, 24. The recesses 20, 24 are formed by round holes.

All the recesses 20, 24, 28 of the structural unit 10 are arranged along spiral lines 22, 26, 30, 32 having in each case more than three recesses 20, 24, 28. The recesses 20, 24, 28 of the structural unit 10 are arranged on intersection points of the spiral lines 22, 26, 30, 32. The spiral lines 22, 26, 30, 32 have in each case a different orientation. The spiral lines 22, 26, 30, 32 have in each case an origin, not visible in any more detail, which is arranged in each case so as to be offset with respect to a center point 34 of the structural unit 10. The origins of the spiral lines 22, 26, 30, 32 are arranged approximately on an elliptic ring, not visible in any more detail, the center point of which is arranged so as to be offset with respect to the center point 34 of the structural unit 10.

The spiral lines 22, 26, 30, 32 are contradirectional to one another with respect to a spiral axis, not visible in any more detail, of the spiral lines 22, 26, 30, 32. Some of the spiral lines 26, 32 run, in comparison with the rest of the spiral lines 22, 30, in opposite directions around their spiral axes away from the respective origins or toward the respective origins.

The distances from in each case two recesses 20, 24, 28 which succeed one another directly along a spiral line 22, 26, 30, 32 vary, in the case of the recesses 20, 24, 28, by less than 50% from the maximum distance between two successive recesses. The recesses 20, 24, 28 which are arranged along the same spiral line 22, 26, 30, 32 are arranged in each case in an angular range of less than 360° along the respective spiral line 22, 26, 30, 32.

The contradirectional spiral lines 22, 26, 30, 32 differ from one another in their number. A number of the spiral lines 22, 30 which run in each case in the same direction with respect to their specific orientation differs from a number of spiral lines 26, 32 which run in an opposite direction thereto.

The number of codirectional spiral lines 22, 30 and the number of contradirectional spiral lines 26, 32 corresponds to a number of the Fibonacci sequence. The number of codirectional spiral lines amounts to 34. The number of contradirectional spiral lines amounts to 21. The numbers of spiral lines 22, 26, 30, 32 correspond to successive numbers of the Fibonacci sequence. The ratio of the two numbers thus constitutes an approximation to the golden section.

The spiral lines 22, 26, 30, 32 correspond to Fibonacci spirals. The codirectional spiral lines 22, 30 and the contradirectional spiral lines 26, 32 are arranged in each case so as to be rotated and offset with respect to one another. The codirectional spiral lines 22, 30 are arranged in each case to be offset to one another and successive spiral lines 22, 30 are in each case rotated through approximately 10.59°. Furthermore, the contradirectional spiral lines 26, 32 are arranged in each case so as to be offset to one another and successive spiral lines 26, 32 are in each case rotated through approximately 17.14°.

The recesses 20, 24, 28 which are arranged along a spiral line 22, 26, 30, 32 have in each case a minimum spacing with respect to the center point 34 which differ from all the minimum spacings with respect to the center point 34 of recesses 20, 24, 28 which are arranged along the two adjacent codirectional spiral lines 22, 26, 30, 32. Consequently, as seen in the circumferential direction about the center point 34 of the structural unit 10, there is no recess 20, 24, 28 of the structural unit 10 which lies directly in the shadow of another recess 20, 24, 28. After each recess 20, 24, 28, a blank space lies on the successive spiral line 22, 26, 30, 32, as seen in the circumferential direction. Furthermore, after a large part of the recesses 20, 24, 28, a blank space lies on the two successive spiral lines 22, 26, 30, 32, as seen in the circumferential direction.

FIG. 2 shows a system with the first and with a further example of the embodiment of the disclosure. The following descriptions and drawings are restricted essentially to a description of the combination of the exemplary embodiments. The set-up, as described above, can also be applied to the further exemplary embodiment, with the exception of the different configuration, particularly with regard to an arrangement of the recesses. It would also be conceivable, however, that the further exemplary embodiment has an alternative set-up according to the disclosure.

FIG. 2 shows a system 36 with the structural unit 10 according to the disclosure and with a structural unit 10′ according to the disclosure. The system 36 is formed by an eccentric grinder 38. Furthermore, the structural unit 10′ is formed by a grinding plate 14. The grinding plate 14 has recesses which are arranged correspondingly to the recesses 20, 24, 28 of the grinding wheel 12. The grinding plate 14 is connected directly to a drive shaft, not visible in any more detail, of the eccentric grinder 38. It would basically be conceivable however, also to have an alternative connection between the grinding plate 14 and a drive unit, not visible in any more detail, of the eccentric grinder 38. The grinding wheel 12 and the grinding plate 14 are positively connected via connection elements, not visible in any more detail. The recesses 20, 24, 28 of the grinding wheel 12 preferably lie exactly on the recesses of the grinding plate 14. Basically, however, an advantageous overlap of the recesses 20, 24, 28 can be achieved by means of the hole pattern 16 independently of an angular position of the grinding wheel 12 on the grinding plate 14. The grinding wheel 12 has, on a side facing away from the grinding plate 14, a grinding surface 40 with granulation. A machining surface 18 is arranged parallel to the grinding surface 40. 

What is claimed is:
 1. A structural unit having a hole pattern for sucking away swarf from a machining surface comprising: at least three recesses arranged at least essentially along a first spiral line; and at least three further recesses arranged at least essentially along a second spiral line, wherein the second spiral line intersects the first spiral line in a region of at least one recess of the at least three recesses and the at least three further recesses.
 2. The structural unit according to claim 1, wherein: the at least three recesses and the at least three further recesses include a plurality recesses, at least a large part of the plurality of recesses are arranged along a plurality of spiral lines, and each spiral line of the plurality of spiral lines has at least three recesses of the plurality of recesses.
 3. The structural unit according to claim 2, wherein at least a large part of the plurality of recesses are arranged at intersection points of the plurality of spiral lines.
 4. The structural unit according to preceding claim 2, wherein at least two spiral lines of the plurality of spiral lines are contradirectional to one another with respect to a spiral axis of the plurality of spiral lines.
 5. The structural unit according to claim 4, wherein the at least two contradirectional spiral lines have different numbers of recesses.
 6. The structural unit according to claim 4, wherein at least one of a number of codirectional spiral lines and a number of contradirectional spiral lines correspond to a number of the Fibonacci sequence.
 7. The structural unit according to claim 1, wherein at least one spiral line of the plurality of spiral lines corresponds at least approximately to a Fibonacci spiral.
 8. The structural unit according to claim 1, wherein each of at least 50% of a portion of recesses which are arranged along a spiral line have a minimum spacing with respect to a center point which differ from all minimum spacings with respect to a center point of recesses which are arranged along two adjacent codirectional spiral lines.
 9. The structural unit according to claim 1, wherein the structural unit is a grinding wheel.
 10. The structural unit according to claim 1, wherein the structural unit is a grinding plate.
 11. A system comprising: a grinding wheel including: at least three recesses arranged at least essentially along a first spiral line, and at least three further recesses arranged at least essentially along a second spiral line, wherein the second spiral line intersects the first spiral line in a region of at least one recess of the at least three recesses and the at least three further recesses; and a grinding plate including: at least three recesses arranged at least essentially along a first spiral line, and at least three further recesses arranged at least essentially along a second spiral line, wherein the second spiral line intersects the first spiral line in a region of at least one recess of the at least three recesses and the at least three further recesses. 